Pulmonary arterial compliance enhancement and control device

ABSTRACT

Devices and methods for increasing a patient&#39;s pulmonary arterial compliance are disclosed. The devices include catheters designed to create a connection between a patient&#39;s venous anatomy and the patient&#39;s pulmonary artery. With the arteriovenous connection various devices can be implanted in order to increase the volumetric compliance of the pulmonary artery. The devices include collapsible and expandable mechanisms which allow the effective pulmonary arterial volume to expand during systole and contract during diastole. The devices may include a balloon or balloon-like implants which cyclically shuttle a working fluid from the pulmonary artery to the vein and back. The devices may be adjustable to provide desired hemodynamic benefits. Methods are disclosed for making and using the inventive devices.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a continuation of U.S. application Ser. No.16/579,787, filed Sep. 23, 2019, which claims the benefit of U.S.Application No. 62/735,623, filed on Sep. 24, 2018, which isincorporated herein in its entirety by reference.

FIELD

The present invention relates to methods and devices for pulmonaryhypertension and heart failure. In particular, the present inventionrelates to methods and devices for treating pulmonary hypertension byincreasing the pulmonary arterial compliance and thereby reducing theright ventricle after-load.

BACKGROUND

Heart failure is a condition effecting millions of people worldwide.Right-sided and left-sided heart failure can both lead to pulmonaryhypertension which can in-turn lead to right heart failure. There existsa need for devices and methods for treating pulmonary arterialhypertension and right heart failure. Pulmonary arterial hypertension isdescribed by increased pulmonary vascular resistance and decreasedpulmonary arterial compliance. While methods of treating increasedpulmonary vascular resistance may include pharmacological treatments ordiuretics there exists a need for treating decreased pulmonary arterialcompliance. To that end devices and methods are disclosed that increasethe volumetric pulmonary arterial compliance in order to reduce theright ventricular after-load and to treat heart failure.

SUMMARY OF THE DISCLOSURE

In general, the present invention concerns treating right heart failureand pulmonary hypertension. To this end, devices and methods aredisclosed herein which may include implanting a compliant element to thepulmonary arterial trunk and left and right pulmonary arteries toincrease the volumetric compliance of the pulmonary arterialvasculature. Furthermore, devices and methods are disclosed herein fortreating pulmonary hypertension which may include accessing thepulmonary artery trunk, delivery an implant and adjusting the implant asneeded to increase the compliance of the pulmonary artery and reduce theafter-load on the right ventricle. Additionally, devices and methods aredisclosed which may include implanting a device inside a patient'spulmonary artery in order to increase the volumetric compliance of thepulmonary artery and providing a means for adjusting the amount ofvolumetric compliance of the artery and further providing a means forrepositioning, retrieving, or removing the implant as needed to treat apatient.

In some embodiments, an implantable compliant device is provided.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 depicts a cross-sectional view of a patient's heart having anexemplary venous wiring catheter in the SVC and an exemplary snarecatheter according to some embodiments of the present teachings.

FIG. 2 illustrates an exemplary device implanted between the superiorvena cava and pulmonary artery according to some embodiments of thepresent teachings.

FIG. 3 illustrates an exemplary device implanted between the superiorvena cava and pulmonary artery according to some embodiments of thepresent teachings.

FIG. 4 illustrates an exemplary device implanted between the superiorvena cava and pulmonary artery according to some embodiments of thepresent teachings.

FIG. 5 illustrates an exemplary device implanted between the superiorvena cava and pulmonary artery according to some embodiments of thepresent teachings.

FIG. 6 illustrates an exemplary device implanted between the superiorvena cava and pulmonary artery according to some embodiments of thepresent teachings.

FIG. 7 illustrates an embodiment of the present teachings, where anexemplary elongate inflation lumen extends from the vasculature into thesuperior vena cava according to some embodiments of the presentteachings.

DETAILED DESCRIPTION

Certain specific details are set forth in the following description andFigs. to provide an understanding of various embodiments. Those ofordinary skill in the relevant art will understand that they canpractice other embodiments without one or more of the details describedbelow. Further, while various processes are described herein withreference to steps and sequences, the steps and sequences of steps arenot to be understood as being required to practice all embodiments ofthe present invention.

Unless otherwise defined, explicitly or implicitly by usage herein, alltechnical and scientific terms used herein have the same meaning asthose which are commonly understood by one of ordinary skill in the artto which this present invention pertains. Methods and materials similaror equivalent to those described herein may be used in the practice ortesting of the present invention. In case of conflict between a commonmeaning and a definition presented in this document, latter definitionwill control. The materials, methods, and examples presented herein areillustrative only and not intended to be limiting.

Unless expressly stated otherwise, the term “embodiment” as used hereinrefers to an embodiment of the present invention.

Unless a different point of reference is clear from the context in whichthey are used, the point of reference for the terms “proximal” and“distal” is to be understood as being the position of a practitioner whowould be implanting, is implanting, or had implanted a device into apatient's anatomy. An example of a context when a different point ofreference is implied is when the description involves radial distancesaway from the longitudinal axis or center of a device, in which case thepoint of reference is the longitudinal axis or center so that “proximal”refers to locations which are nearer to the longitudinal axis or centerand “distal” to locations which are more distant from the longitudinalaxis or center.

As used herein, the terms “subject” and “patient” refer to any animal,such as a mammal like livestock, pets, or humans. Specific examples of“subjects” and “patients” include, but are not limited, to individualsrequiring medical assistance, and requiring treatment for symptoms ofheart failure.

FIG. 1 depicts a cross-sectional view of a patient's heart 101 includinga superior vena cava 103 (SVC), an inferior vena cava 104 (IVC), a rightatrium 105 (RA), a right ventricle 107 (RV), and a pulmonary artery 109(PA). The pulmonary artery includes a right branch 111 and a left branch113. A venous wiring catheter 115 is shown in the SVC and directedtowards the right branch of the pulmonary artery. The catheter isconfigured to allow for directional control of the catheter tip and isconfigured to deliver a wire 117 through the wall of the SVC and intothe lumen of the pulmonary artery. The wire is depicted having crossedinto the pulmonary artery. A second pulmonary artery catheter 119 isdepicted and has been threaded through the SVC, through the right atriumand right ventricle and into the pulmonary artery trunk. This catheteris configured to allow for passage of a snaring catheter 121 to snarethe wire in the pulmonary artery. In this manner the catheters of FIG. 1represent a means for creating an initial puncture from the SVC into thepulmonary artery and for being able to access that puncture from the SVCand from the pulmonary artery.

The venous wiring catheter of FIG. 1 may be configured to be steerableor articulating, for example, by using a pull wire to generate apredetermined curve when the wire is tensioned. The venous wiringcatheter of FIG. 1 may feature a pre-determined curved shape useful forpointing towards the PA. The wiring catheter may be made out of anysuitable material or construction including Nylon, PEBAX, polyethylene,polyurethane, PEEK, or any other polymeric material. The wiring cathetermay include wound or braided support structures including braidedstainless steel. The wiring catheter may be configured with an internaldiameter of between 0.5 mm and 1.5 mm.

The wire of FIG. 1 may be made from any suitable material. For example,the wire may be made from Nitinol or stainless steel. The wire mayinclude a sharpened distal segment for penetrating the vein and artery.The wire may include a flexible segment just proximal to the distal tipsuch that when supported by the delivery catheter the wire hassufficient column strength to cross the vessel walls but once throughthe walls the wire is not able to further cross back outside thepulmonary artery. The wire may be configured with a helical coil tipsuch that torque may be used to force the wire across the vessel walls.The wire may instead be replaced by an off the shelf component such as aBrockenbrough needle or similar device. The wire may instead be a needlelike assembly, for example, a laser cut hypotube may be used as a vesselcrossing wire. The wire may be configured to deliver energy in order tocross the vessel walls, for example, electrical energy, RF energy, orheat energy may be used to assist the wire crossing.

The pulmonary artery catheter of FIG. 1 may be made from any of the samematerials or constructions as described above. The pulmonary arterycatheter may feature a predetermined shape useful for accessing thepulmonary artery. The pulmonary artery catheter may be configured toride over an interventional wire or balloon catheter, such as aSwan-Ganz catheter. The pulmonary artery catheter may be any reasonablesize and length. For example, the pulmonary artery catheter may be 80 cmlong and feature an outer diameter of approximately 5 mm and an internaldiameter of 3.5 mm. The pulmonary artery catheter may have deflecting orarticulating segments, for example, curves that can be adjusted with theuse of an internal pull wire. The pulmonary artery catheter isconfigured to create a lumen through which additional devices may bedelivered to the pulmonary artery. For example, as shown in FIG. 1 , thepulmonary artery catheter may be configured to deliver a snare which canbe used to capture and externalize the vessel crossing wire. Onceexternalized the wire and pulmonary artery catheter can be used todeliver a pulmonary artery compliance enhancement device as describedherein.

The snare of FIG. 1 may be a custom basket snare designed to fill theinternal diameter of the pulmonary artery. The snare of FIG. 1 one maybe a simple goose-neck snare. The snare of FIG. 1 may instead be acommercially available vascular snare.

FIG. 1 depicts a method for creating a connection from the SVC to the PAin a patient. This connection may then be used to deliver additionalinventive devices or embodiments of the present invention, for example,a device may be delivered over the wire and into the pulmonary arterywhich effectively increases the volumetric compliance of the pulmonaryartery. In some embodiments once the wire has been snared andexternalized an enlarged pathway or shunt may be created between thesuperior vena cava and the pulmonary artery. In some embodiments theenlarged pathway is created by advancing a dilating catheter over thewire. In embodiments the enlarged pathway or shunt is created by cuttingthe tissue surrounding the wire or ablating the tissue around the wire.

Turning now to FIG. 2 , a patient's superior vena cava 103 and pulmonaryartery 109 are depicted. A shunting device 201 has been implanted;creating a pathway between the superior vena cava and the right branch111 of the pulmonary artery. The shunting device includes a tubular body203 with an internal diameter for fluid passage and a number ofanchoring arms 205. The shunting device is configured to allow blood orfluid to flow through the internal diameter of the shunting device andto prevent blood from passing around the arms of the shunting device orinto the space between the vessels. A stent-like compliant implant 207resides in the pulmonary artery. The stent like compliant implantincludes a metallic skeleton structure (not shown) and a thin coveringfilm. The compliant implant includes a proximal anchoring section 209and a distal anchoring section 211. The proximal and distal anchoringsection are designed to anchor the implant to the internal walls of thepulmonary artery and to prevent blood flow around the edges of theimplant. The compliant implant includes a reversibly collapsible andexpandable segment 213 between the two anchoring segments.

The shunting device of FIG. 2 may be configured to be delivered in acollapsed state and then expanded or allowed to expand into position ina previously created shunt between the SVC and pulmonary artery. Theshunting device of FIG. 2 may be made from a single laser cutsuperelastic or shape memory nitinol hypotube. The shunting device maybe made from any suitable material, including Nitinol, stainless steel,polyurethane, PET, PEEK, cobalt chromium alloys, or other metallicmaterials, alloys, or polymeric materials. The shunting device may bemade from two telescoping halves, an arterial half and a venous half.The shunting device may be covered by a fabric or film in order toimprove haemostatic sealing against the vessel walls. The shuntingdevice may instead by covered by a mammalian pericardium such as bovinepericardium. The covering may be sewn to the shunting device atpredetermined attachment points. The shunting device may includeelements designed to compress the wall of the vessels together. Theshunting device may include secondary anchoring elements, such as barbsor hooks which engage the vessel walls. The internal diameter of theshunting device may be configured to allow sufficient fluid flow throughthe device such that during systole the collapsible portion of thecompliant implant is allowed to collapse and force fluid through theshunt and during diastole the compliant implant is allowed to return toits pre-determined lower energy state. For example, the internaldiameter of the shunting device may be between 4 mm and 10 mm.

The shunting device may be delivered over a wire which has been passedthrough the vessel walls, such as depicted in FIG. 1 . The shuntingdevice may be configured to forcibly expand the passageway between thesuperior vena cava and the pulmonary artery. The shunting device may bedelivered from the superior vena cava side or from the pulmonary arteryside or from both sides in a stepwise or simultaneous manner.

The compliant implant may include a skeleton structure that is made fromany suitable material including any of the materials referenced above.The compliant implant may include a covering material such as a film,fabric, or other cover. The compliant implant may be covered in asimilar manner to a covered stent, for example, a covered stent used totreat abdominal aortic aneurysms. The compliant implant may be coveredby a thin film of expanded PTFE material. The compliant implant may becovered by a hydrogel material. The covering may be sewn to thestent-like implant at various attachment points. In embodiments thecompliant implant includes a skeleton structure made from a laser cutNitinol hypotube which has been expanded and heat set to a suitableouter diameter. In embodiments an ePTFE film is attached to the expandedNitinol tube. In some embodiments the skeleton structure is a woven orlaser cut stainless steel structure which is expanded into position byinflating a balloon inside the structure. The anchoring segments of theimplant may include additional compliant material adapted for creating ahaemostatic seal around the internal diameter of the artery. In someembodiments the anchoring segment includes a folded up skirting materialwhich helps to seal the ends of the device to the vessel wall. Thecompliant implant may include a substantially flattened section, whichis configured to hold a flattened shape under a first amount of internalblood pressure and which is configured to expand to a rounded shapeunder a second higher amount of internal blood pressure. In embodimentsthis first and second pressures can be adjusted by incorporating pullwires or stiffening wires into the structure of the implant. Thecompliant implant is configured to take up as much length of the rightbranch of the pulmonary artery as possible while not blocking any of thedistal pulmonary artery passages. For example, the compliant implant maybe 6 cm long. The compliant implant may be keyed to the shunting devicesuch that the collapsible portion of the implant substantially faces theshunting device. The shunting device may protrude into the pulmonaryartery enough such that when the compliant implant expands due to thesystolic pressure wave the expansion around the shunt is limited,thereby allowing the fluid to be forced through the shunt and preventingthe compliant implant from prematurely closing off the fluid pathcreated by the shunt.

The compliant implant and shunting device of FIG. 2 combine to increasethe effective pulmonary arterial volumetric compliance. The internalfluid volume of compliant implant is designed to expand during cardiacsystole and return to its low energy state during cardiac diastole.

Turning now to FIG. 3 embodiments of the present invention are depicted.A patient's superior vena cava 103 and pulmonary artery 109 are shown incross section. A shunting device 201 has created a passageway betweenthe SVC and the pulmonary artery. The shunting device includes aplurality of anchoring arms 205 on the venous and arterial sides of theshunt. A cross section of a compliant stent-like implant 207 is shownresiding inside the pulmonary artery. The compliant implant includes agenerally round wall segment 301 and a substantially flattened wallsegment 303. The substantially flattened wall segment represents areversibly collapsible and expandable segment as described above. Thecompliant implant includes proximal and distal anchoring segments (notshown) which have a generally round cylindrical shape and which preventblood from flowing from the pulmonary artery around the device. A seriesof tubular extrusions 305 are incorporated into the wall of thecompliant implant and are shown in cross-section. Large arrows 307 areshown to depict the flow of blood into and out of the shunting device.Smaller arrows 309 are shown to depict the outward force on thecompliant device caused by the pulmonary artery pressure wave.

The compliant implant of FIG. 3 is configured to reversibly expand andcollapse during a patient's cardiac cycle. For example, during systolethe flattened wall of the compliant implant is configured to expand andsubstantially fill the space of the pulmonary artery, in the processforcing blood or fluid (saline, radio-opaque contrast, etc.) through theshunting device. During diastole the flattened wall is configured toreturn to its lower energy shape as depicted in FIG. 3 . The compliantimplant may be made from any of the materials as described above. Forexample, the compliant implant may be made from a laser cut Nitinolhypotube which has been heat set into the desired shape. The compliantimplant may include a covering material such as described above. Forexample, the compliant implant may be entirely covered by a sheath ofexpanded PTFE polymer. In some embodiments the compliant implant is madeof or surrounded by a wall of hydrogel material. In some embodiments thecompliant implant is made entirely by a specially shaped, implantable,thin walled, annular balloon.

The tubular extrusions of FIG. 3 are configured for accepting a numberof stiffening bars as necessary. For example, a single stiffening barmay be inserted in the central tubular extrusion for some patients,while other patients may require the use of all three stiffening bars.In this manner the tubular extrusions and stiffening bars represent ameans for adjusting the pressure differential required to collapse andexpand the compliant implant. The stiffening bars may be made from anysuitable material including stainless steel, Nitinol, PEEK, polyimide,polyurethane, PTFE, FEP, ultra-high molecular weight polyethylene,cobalt-chromium alloys, or other metallic alloys or polymeric materials.The stiffening bars may be braided or twisted cables. The stiffeningbars may feature composite construction, for example, a stainless steelcoil wrapped around a central elastic tensile member may be used. Thestiffening bars may be made from laser cut tubing material, for example,a laser cut Nitinol hypotube may be used or a laser cut stainless steeltube may be used. In embodiments the stiffening bar and tubularextrusion may instead be a stacked stainless steel coil, the coil beingsewn into or otherwise attached to the compliant implant. Through thecoil an elastic tensioning member resides. The elastic tensioning membermay be made from any suitable material including UHMWPE, PET,polyurethane, silicone rubber, or other materials. The elastictensioning member may feature braided or twisted strands. The elastictensioning member may feature a high stiffness or elastic modulus and isconfigured to undergo primarily elastic elongation under a predeterminedamount of tension. The tensioning member is fixedly attached to thedistal end of the stacked coil. The tensioning member and stacked coilare configured such that an amount of tension may be applied to thetensioning member, thereby compressing the stacked coil. This tensionmay be locked in by a secondary locking element, such as a sliding knot,a crimped tube, or a cam or ratcheting mechanism. The amount of tensionon the tensioning member can be adjusted in order to vary the bendingstiffness of the stacked coil arrangement. In this way the stacked coiland tensioning member represent a means for adjusting the stiffness ofthe substantially flat walled section of the compliant implant. Thisadjustable stiffness of the compliant implant in turn adjusts the amountof differential pressure required to collapse or expand the compliantimplant. In embodiments the tubular extrusions of FIG. 3 may beconfigured to support an elongate, inflatable compliant or non-compliantballoon. The amount of pressure used to inflate the balloon can bevaried, for example, significant pressure can be applied to the fluid inthe balloon thereby increasing the stiffness of the collapsible portionof the compliant implant. In some embodiments the amount of fluid usedto inflate the stiffening balloons may be adjusted by a user in order tocreate a collapsible implant with a predetermined stiffness and whichcollapsed at a desired pressure differential.

The shunting device of FIG. 3 may be made of any of the materials andconstructions as described above. The shunting device may besubstantially similar to the shunting device depicted in FIG. 2 .

Turning now to FIG. 4 , embodiments of the present invention aredepicted. A patient's superior vena cava 103 and pulmonary artery 109are depicted. The pulmonary artery has a left branch 113 and a rightbranch 111. A shunting device 201 with a tubular body 203 and anchoringarms 205 has been implanted into a shunt that was created between theSVC and the pulmonary artery. A stent-like compliant implant 207 withproximal anchoring section 209, distal anchoring section 211, andreversibly expandable section 213 has been deployed in the pulmonaryartery. A venous compliant implant 401 has been deployed in the superiorvena cava. The venous compliant implant may include a proximal anchoringsection and a distal anchoring section. The anchoring sections aredesigned to fix the implant to the inner walls of the SVC as well as toprevent fluid flow around the ends of the device. The venous compliantimplant may be made in the same manner and with the same materials asthe stent-like compliant implant in the pulmonary artery. The venouscompliant implant may have a stent-like skeleton structure (not shown)and a covering element. The venous compliant implant may be manufacturedin a manner similar to that of a covered stent. The venous compliantimplant may be manufactured in a manner similar to that of a coveredstent designed to treat aortic abdominal aneurysms. The venous compliantimplant includes a reversibly collapsible section between the twoanchoring sections. The reversibly collapsible section may have anadjustable stiffness, using for example, pull wires or stiffening barsto adjust the stiffness of the collapsible segment.

The venous compliant implant of FIG. 4 may be delivered using a deliverycatheter. The venous compliant implant may be delivered in a collapsedconfiguration and allowed to expand in the SVC. The venous compliantimplant may be delivered in a collapsed configuration and expandedmechanically, for example, with the use of a balloon catheter. Thevenous compliant implant may be keyed in delivery such that thereversibly collapsible segment faces the shunting device.

The complaint implants and shunting device of FIG. 4 together create ahaemostatic fluid reservoir inside the patient's vasculature. Afterdelivery of the implants the blood volume may be removed from thehaemostatic fluid reservoir and replaced with saline. In embodiments thevenous compliant delivery device is delivered alongside a small fluidexchange catheter. The fluid exchange catheter is configured tosubstantially replace any fluid in the haemostatic reservoir with salineor with a mixture of saline and radio-opaque contrast medium. Inembodiments the amount of fluid injected into the haemostatic region isadjusted in order to control the relative pressure in the haemostaticregion. In embodiments fluid is injected into the haemostatic fluidreservoir until the venous compliant device collapses a pre-determinedamount. In embodiments fluid is injected into the haemostatic fluidreservoir until a desired amount of fluid volume cycles from thearterial side of the reservoir to the venous side of the reservoirduring each cardiac cycle. In some embodiments the venous compliantimplant includes an elongate fluid filling port which can be used tofill the haemostatic fluid reservoir. In some embodiments the fluidfilling port is configured to releasably engage with a fluid fillingcatheter. For example, after implantation a first amount of fluid can beinjected into the haemostatic fluid reservoir and the catheters may beremoved. In subsequent procedures the fluid filling port could then beengaged by a filling catheter, for example, by snaring the fluid fillingport and then advancing the filling catheter over the snare until itengages the fluid filling port. In this way the compliant implants andfluid filling ports could be used to adjust the amount of fluid injectedinto the haemostatic fluid reservoir as desired by a clinician.

The compliant implants and shunting device of FIG. 4 represent a meansfor increasing the volumetric compliance of the pulmonary artery. Thecompliant implants are configured to reversibly expand and collapse,thereby changing the internal blood volume in the region of theimplants. The compliant implants are further configured to expand andcollapse at predetermined cardiac pressures. In embodiments the pressuredifferential required to expand and collapse the compliant implants isadjustable by a clinical user.

In some embodiments the compliant implants and shunting device may beconnected to a separate pump. For example, a fluid pump could beimplanted under the skin in a similar manner to a pacemaker. Animplantable fluid delivery catheter could connect the implanted pump tothe compliant implants. The implantable pump would then be configured tocyclically pump fluid into the reservoir during desired points in thecardiac cycle in order to increase the effective compliance of thepulmonary arteries.

Turning now to FIG. 5 , embodiments of the present invention aredepicted. A patient's heart 101 is shown in cross-section, including asuperior vena cava (SVC) 103, a right atrium 105, an inferior vena cava104, a right ventricle 107, and a pulmonary artery 109. The pulmonaryartery includes a left branch 113 and a right branch 111. A compliantimplant 501 resides in the pulmonary artery. The compliant implantincludes a proximal section 503, a left branch 505, and a right branch507. The compliant implant includes a generally cylindrical proximalanchoring section, as well as generally cylindrical left branchanchoring section and right branch anchoring sections. The compliantimplant includes a reversibly collapsible and expandable segment. Thereversibly collapsible segment extends from the right branch of thecompliant implant and into the proximal section of the compliantimplant. An arterio-venous shunt 509 has been formed between thepulmonary artery and the superior vena cava. This shunt could be createdby any suitable means, including RF ablation, cutting, or puncturing anddilating. A shunting device similar to that described above may beimplanted to maintain or create the shunt. The compliant implant mayinclude a metallic or polymeric skeleton structure. The compliantimplant may include a polymeric or biological covering material. Inembodiments the compliant implant may be similar in construction to abifurcated covered stent.

The compliant implant of FIG. 5 may function in a similar manner to theembodiments described above. For example, during the diastolic phase ofthe cardiac cycle the collapsible and expandable portion of thecompliant implant is collapsed into the fluid diameter of the compliantimplant. During the systolic phase of the cardiac cycle the collapsibleand expandable portion of the compliant implant expands such that thewall of the implant is nearly in contact with the wall of the pulmonaryartery. This action temporarily results in blood or saline being pushedfrom the pulmonary artery and into the superior vena cava. The result ofthe expansion and collapse of the compliant implant during a cardiaccycle is that the volumetric compliant of the pulmonary arteryvasculature is substantially enhanced.

In embodiments, the device of FIG. 5 includes a compliant implantdelivered into the superior vena cava. In some embodiments the compliantimplant in the superior vena cava and the pulmonary artery togethercreate a closed system where blood, saline, or another fluid isalternatively pushed from the superior vena cava and pulmonary artery asthe pressure gradient changes between the two vessels.

In embodiments, the space between the compliant implant of FIG. 5 andthe inner walls of the pulmonary artery are filled by a compliantballoon. In some embodiments the compliant balloon extends into thesuperior vena cava and create a haemodynamic seal between the twovessels. In some embodiments a multi-chambered compliant balloon fillsthe space around the compliant implant. The multiple chambers eachextend from the pulmonary artery into the superior vena cava. Themultiple chambers are configured to collapse and transfer fluid from thepulmonary artery to the SVC. The multiple chambers may be configured toallow more complete evacuation of the fluid form the pulmonary arteryside of the implant. In embodiments the compliant implant has aninflation lumen incorporated into the walls of the implant. Inembodiments the inflation lumen may be used to alter or adjust thestiffness of the reversible collapsible and expandable segment of thecompliant implant.

Turning now to FIG. 6 , embodiments of the present invention aredepicted. A patient's superior vena cava 103 and pulmonary artery 109are shown. The pulmonary artery includes a left branch 113 and a rightbranch 111. A connection has been made between the superior vena cavaand the pulmonary artery. The connection may be made using any suitabledevices or methods, including those described above and depicted in FIG.1 . A two chambered implantable balloon 601 is shown implanted into thepulmonary artery and SVC. The balloon includes a venous side 603, anarterial side 605, and a waist section 607. The waist section may beconfigured to substantially compress the walls of the pulmonary arteryand SVC together in order to prevent blood flow around the device ouroutside the walls of the vessels. The waist section may be configured tobe substantially more rigid than the rest of the balloon. The waistsection of the balloon may incorporate features for adhering the balloonto the tissue, for example, ridges may be built into the surface of theballoon, or compressible fabric may be attached to the waist of theballoon. The waist section of the balloon may include hooks or similarstructures for engaging the tissue. The arterial side of the balloon mayfeature any suitable shape, for example, an annular balloon may be used.The arterial side of the balloon is compliant and is configured to bereversibly collapsible. The arterial side of the balloon may extend intothe pulmonary artery trunk or across and into the left branch of thepulmonary artery. The arterial aspect of the balloon is sized in orderto provide sufficient volumetric compliance to treat pulmonaryhypertension. For example, the arterial aspect of the balloon maycontain about 25 mL of saline during the diastolic phase of the cardiaccycle and may collapse to a volume of about 10 mL during the systolicphase of the cardiac cycle. The venous side of the balloon may featureany suitable size or shape. For example, the venous side of the balloonmay feature a hemi-cylindrical shape, or a crescent shape, or may simplybe an elongate generally cylindrical shape. The venous side of theballoon is configured to be generally compliant. The venous side of theballoon is configured to expand at a known pressure differential andwith pre-determined pressure-volume relationship effect. The venous sideof the balloon may incorporate features designed to allow for rapidexpansion of the balloon, for example, corrugations or folds may beincorporated into the shape of the balloon in order to facilitate theexpansion of the balloon. The venous side of the balloon may beconfigured to expand from a first volume to a second larger volume withonly minor changes in pressure. The venous side of the balloon mayinstead be configured to expand from a first volume to a second largervolume but only when subjected to a predetermined increase in pressure.The compliance behaviour of the balloon may be configured such that adesired and predetermined pressure-volume relationship is achieved. Inembodiments the venous side of the balloon is compliant across a largerange of inflated volumes, for example, from 20 mL to 40 mL. The venousside of the balloon may then be inflated as necessary to normalize thepressure on the arterial side of the balloon such that the arterial sideof the balloon collapses during systole and expands during diastole. Theballoon of FIG. 6 may be anchored to the SVC or the pulmonary artery byan optional stent-like anchor. The balloon of FIG. 6 may feature anelongate non-compressible skeleton structure along one edge of theballoon. For example, a steel ribbon may be incorporated into the wallof the balloon from the neck feature to the end of the balloon furthestfrom the neck feature. This ribbon may be configured to substantiallystiffen the balloon in one direction, thereby preventing the balloonfrom changing shape due to the rush of blood during the cardiac cycle.In this manner the balloon chambers may be configured to expand andcontract while substantially maintaining its general shape. The balloonof FIG. 6 may be inflated by a removable inflation device. The balloonof FIG. 6 may be inflated by a permanent or implantable inflation devicewhich may be access in follow up procedures to further treat thepatient.

The balloon of FIG. 6 may be made from any suitable material includingpolyurethane, latex rubber, PET, PE, or other suitable polymericmaterials. The balloon may be inflated with any suitable fluid,including Saline, water, contrast medium, air, nitrogen, or helium.

Turning now to FIG. 7 , embodiments of the invention are depicted. Across-section of a patient's heart 101 is shown, including a superiorvena cava 103, an inferior vena cava 104, a right atrium 105, a rightventricle 107, and a pulmonary artery 109. The pulmonary artery is splitinto a right branch 111 and a left branch 113. An elongate inflationlumen 701 extends from the vasculature into the superior vena cava andthrough an arterial-venous opening 705. The inflation lumen connects tocompliant balloon 703.

In embodiments the inflation lumen 701 is connected to anelectromechanical pump. The pump is configured to reversibly push afluid through the lumen and into the balloon. The pump may beimplantable, and may reside in the location typically reserved forpacemakers. The pump may be implanted in a similar manner to apacemaker. In embodiments the balloon may include pressure sensingelements. In embodiments the balloon or inflation lumen may includeelectrical sensing elements, similar to that of an ECG lead. Thepressure sensing and electrical sensing elements may be configured toelectronically send the pressure and electrical information to theimplantable pump. The implantable pump may be configured to use thisinformation to determine, programmatically or algorithmically, when andhow much fluid to pump into or out of the balloon. In embodiments theinflation lumen, balloon, and sensing elements may therefore act in amanner similar to an intra-aortic balloon pump. The balloon of FIG. 7may include pre-folded creases in order to facilitate rapid inflationand deflation of the balloon. The balloon, pump, and inflation lumen maybe configured to pump approximately 20 mL of fluid into and out of theballoon during the cardiac cycle. The fluid moved by the pump may be anysuitable fluid, including saline or helium. In some embodiments theballoon, pump, and inflation lumen may be implanted simultaneously witha pacemaker lead or leads. In some embodiments a pacemaker andimplantable pump are designed to work together to ensure that the timingof the balloon pulsation is optimal for increasing the effectivearterial compliance by way of inflating and deflating the balloon. Insome embodiments the inflation lumen is externalized through animplantable port and connected to an external inflation machine, similarto that of an inter-aortic balloon pump. In some embodiments theballoon, inflation lumen, and arterial-venous connection of FIG. 7 maybe used in conjunction with an external pumping machine for emergencycare following a sudden decrease in RV function. In some embodiments theballoon and inflation lumen is connected to an extra-corporal electronicpump. In some embodiments the balloon, inflation lumen, and externalpump work in concert with an ECG in order to provide counter-pulsationand in order to lower the RV afterload in a patient. In some embodimentsthe invention as depicted in FIG. 7 may be used for temporary palliativecare, for example, for treating a patient with severe right ventriculardisfunction and congestive heart failure. In some embodiments theinvention as depicted in FIG. 7 may be used as a bridge to recovery in asimilar manner to left ventricular assist devices, where a patient whohas undergone an acute cardiac event can have their RV afterload reducedand right sided cardiac output augmented temporarily allowing their RVto heal following an injury, such as a myocardial infarction.

What is claimed is:
 1. A method of treating pulmonary hypertension in apatient, the method comprising: forming an opening between a superiorvena cava of the patient and a pulmonary artery of the patient with atool supported by a venous catheter; delivering a shunt to the opening;and securing the shunt in the opening to divert blood flow from thepulmonary artery into the superior vena cava.
 2. The method of claim 1,wherein the tool comprises a wire with a sharp distal end, the formingstep comprising penetrating a wall of the superior vena cava and a wallof the pulmonary artery with the sharp distal end of the wire.
 3. Themethod of claim 1, wherein the tool comprises a needle, the forming stepcomprising penetrating the wall of the superior vena cava and the wallof the pulmonary artery with the needle.
 4. The method of claim 1,further comprising delivering a wire through the opening.
 5. The methodof claim 4, wherein the step of delivering a wire comprises deliveringthe wire from the venous catheter through the opening into the pulmonaryartery.
 6. The method of claim 4, further comprising snaring an end ofthe wire after it passes through the opening.
 7. The method of claim 6,further comprising advancing an arterial catheter into the pulmonaryartery and advancing a snare out of the arterial catheter.
 8. The methodof claim 1, wherein the delivering step comprises delivering the shuntin a collapsed state and expanding the shunt in the opening.
 9. Themethod of claim 1, wherein the delivering step comprises advancing theshunt over a wire extending through the opening.
 10. The method of claim9, wherein the delivering step further comprises advancing the shuntover the wire through the superior vena cava to the opening.
 11. Themethod of claim 9, wherein the delivering step further comprisesadvancing the shunt over the wire through the pulmonary artery to theopening.
 12. The method of claim 1, further comprising compressing wallsof the superior vena cava and the pulmonary artery together.
 13. Themethod of claim 1, wherein the shunt comprises a plurality of anchoringelements, the method further comprising engaging a wall of the superiorvena cava and a wall of the pulmonary artery with the anchoringelements.
 14. The method of claim 1, wherein the shunt comprisesanchoring arms, the method further comprising disposing a plurality ofanchoring arms on each side of the opening.
 15. The method of claim 1,further comprising expanding the opening with the shunt.
 16. The methodof claim 1, wherein the shunt comprises a fluid passageway, the methodfurther comprising directing blood from the pulmonary artery through thefluid passageway to the superior vena cava.
 17. The method of claim 16,wherein the fluid passageway has a diameter between 4 mm and 10 mm. 18.The method of claim 1, wherein the shunt comprises a laser cut tube. 19.The method of claim 1, wherein the shunt is covered with fabric or film.